Isreeli



NOV. 17, 1959 'J |5REEL| Re. 24,736

DIALYZERS Original Filed April 25, 1957 s Sheets-Sheet 1 INVENTOR.

- Jc/P Bree/z BY 6% M k ATTORNEYS J. lSREELl Nov. 17, 1959 DIALYZERS 3Sheets-SheetQ Original Filed April 25, 1957 INVENTOR. JZc/ [Free/1' BY(5% M ficn (Ea-L ATTORNEYS I Re. 24,736

J, ISREELI nmuzsas Nov. 17, 1959 :s Sheets-Sheet 3 o i inal Filed. April25,}95'1 FIG. 8

FIG. 6

United States Patent Ofilice Re. 24,736 Reissued Nov. 17, 1959 DIALYZERSJack Isreeli, Tuckah'oe, N.Y., assignor, by mesne assignments, toTechnicon Instruments Corporation, Chauncey, N.Y., a corporation of NewYork Original No. 2,864,507, dated December 16, 1958, Serial No.655,093, April 25, 1957. Application for reissue December 22, 1958,Serial No. 782,341

14 Claims. (Cl. 210-321) Matter enclosed in heavy brackets appears inthe original patent but forms no part of this reissue specification;matter printed in italics indicates the additions made by reissue.

The present invention relates to dialyzer-s.

An object of the present invention is the provision of a dialyzer ofgenerally simplified construction which nevertheless is highly efficientin operation, the use of which is set forth in great detail in thepatent to Skeggs, No. 2,787,149, and assigned to the assignee of thisapplication.

Another object is to provide a dialyzer having readily accessible fluidinlets and fluid outlets at each side of the dialyzer membrane. In thisconnection, it is a more specific object of the invention to providesaid outlets in juxtaposition at outer edge portions ofthe dialyzermembers between which the membrane is mounted.

A further object is the provision of a dialyzer apparatus in which thenumber of convolutions in each of the dialyzer members between which themembrane is mounted can be greatly increased in number with a verylittle increase in the diameter of said members over prior artdialyzer-s.

A further object is to provide a highly novel clamping arrangement forclamping together in fluid-tight relation the dialyzer members betweenwhich the dialyzer membrane is disposed, the arrangement being such thatthe members are retained against relative tilting so as to prevent theseparation of the fluid passages provided in the confronting faces ofsaid members.

Another object of the invention is to provide a dialyzer constructionand arrangement of dialyzer elements to enable the operative capacity ofthe dialyzer to be increased without increasing the diameter of theapparatus.

Another object is to provide improved means for releasably clamping thedialyzer parts in operative relation.

A still further object is the provision of a highly novel arrangementfor eflecting registry of the fluid passages defined in the opposingfaces of the dialyzer members.

The above and other objects, features and advantages of the presentinvention will be more fully understood from the following descriptionconsidered in connection with the accompanying illustrative drawings.

In the drawings which illustrative the best mode presently contemplatedof carrying out the invention:

Fig. 1 is a plan view of a dialyzer apparatus pursuant to the presentinvention;

Fig. 2 is a sectional view, on an enlarged scale, taken on the line 22of Fig. 1;

Fig. 3 is a fragmentary sectional view, on an enlarged scale, taken onthe line 33 of Fig. 2;

Fig. 4 is a plan view of one of the dialyzer members in which thegrooves for the passage of fluid are defined, the face or surfacethereof in which said grooves are defined being uppermost;

Fig. 5 is a fragmentary sectional view, on a greatly enlarged scale,taken on the line 55 of Fig. 1;

Fig. 6 is a view similar to Fig. 1 showing the presently preferred formof the invention;

Fig. 7 is a vertical sectional view, on a larger scale, on the line 77of Fig. 6;

Fig. 8 is a fragmentary sectional view, on a large scale, on the line 88of Fig. 6; and

Fig. 9 is a fragmentary sectional view, on a large scale, on the line 99of Fig. 6..

Referring to the drawings in detail, the reference numeral .10 indicatesa dialyzer device or apparatus pursuant to the present invention. Thedialyzer 10 comprises a dialyzer membrane 14 mounted between a pair ofgrooved plates or members 16 which are clamped together by a clampingarrangement 20.

The members 16 are similar in construction and, as here shown, eachmember 16 is constituted by a circular plate or disc formed of asuitable material, for example and not by way of limitation, the membersare formed of lucite and are transparent. At its face 18, each member isprovided with a continuous spiral groove 20 which is reflexedsubstantially centrally along the extent thereof, as at 22, so that theterminals 24 and 260i the groove 20 are in juxtaposition and areadjacent the periphery of the platen '16. As here shown, the plates 16are provided with the notched portions 28 and 30 in the peripherythereof. Each plate is bored, as at 3232, from each notched portionthereof to the adjacent terminal of the groove 20. Each bore 32 isprovided with an enlarged portion or seat 34 which extends from theadjacent notch so as to receive a nipple 36 therein which extendsoutwardly of the associated notch. The projecting portion of each nipple36 is adapted to receive one end of a fluid conduit 38 or 39, as thecase may be.

In view of the foregoing, it will be apparent that each dialyzer plateor member 16 is provided with apair of nipples 36 at the peripherythereof, one of the nipples constituting a fluid inlet and the othernipple constituting a fluid outlet, as hereinafter described in detail.Each plate 16 is provided also with a circular cutout 40 at the centerthereof. In addition to the notches 28 and 30 .provided at the peripheryor circumference thereof, each plate 16 is provided at the peripheral orcircumferential edge thereof with a stepped formation 40A, the functionof which is hereinafter described. Each plate 16 is also provided,adjacent the periphery thereof with the eccentrically related bores 4242each of which has a seat defining portion 44A of larger diameteradjacent the grooved face 18 thereof.

The clamping means 20 is constituted by a pair of backing plates orpressure transmitting members 4444 for the dialyzer members 1616,respectively, a pair of clamping members 46-46 which act upon thebacking plates, and the cooperating stud 48 and nut 50.

The backing plates 44, as here shown, are circular members which arepreferably formed of a suitable metal, for example and not by way oflimitation, stainless steel. vided with a plurality of equally spacedholes 52 arranged between a circular central opening 54 and the marginalor circumferential edge 56 thereof. Said holes 52, as best seen in Fig.2, overlie the grooved portions of the dialyzer members as to make thegrooves therein visible through the backing plates and, in addition, theholes provide a desired degree of flexibility to the backing members 44.

clamping member is provided with a circular groove 58.

The clamping members 46 are circular members formed of a suitablematerial, preferably stainless steel, and each is provided at themarginal edge thereof with a lateral circular projection or-rib[circular rim] which is adapted to engage in the circular groove 58defined in the associated backing member 44.

Said plates are relatively thin and are pro-.

In the outer surface thereof, each The clamping mechanism 20 includes acheck nut 62 which is provided on the stud 48 to form a shoulder for theclamping action, as hereinafter described, the nut SObeing operable toadjust the pressure providedby the clamping apparatus 20. A washer 66 isseated in the nut 50 so as to be interposed between the nut and theadjacent clamping element 46. The nut 50 is provided with four equallyspaced holes 66A in the periphery thereof for adjusting the latter onthe stud 48, as hereinafter described.

The dialyzer is also provided with a spill plate 76 which, as hereshown, is suitably secured, as by the bolts 72-72, to a suitable support74, spacers 73 being interposed between the support and the spill plate.

When the dialyzer unit 10 is assembled for operation With the spillplate 70, suitably supported, as illustrated, the lower clamping member46 (viewing Fig. 2) is secured to the spill plate 70 by means of thebolts 76-76. The stud 48 extends through the spill plate 70, the lowerclamping member 46, the lower backing member 44, the lower dialyzerplate 16, the membrane 14, the upper dialyzer plate 16, the upperbacking member 44, the upper clamp member 46, and the nut 50. It will benoted that the spiral groove in the lower plate is in registry with thespiral groove 20 in the upper plate 16 with the membrane 14 disposedtherebetween. As here shown, the membrane 14 is a circular element ordisc formed of a suitable dialyzing material, for example and not by wayof limitation, uncoated cellophane, which is clamped in position betweenthe confronting faces of the plates 16 in which the grooves 20 aredefined. In order to assure the absolute registry of the grooves in theupper and lower dialyzer plates 16, a socket pin 78 is inserted in thebore 42 of the lower plate 16, said socket pin being seated in the seat44A defined therein and extending to the surface 18 of said plate, and acomplementary pin 80 is inserted into the socket 82.0f the socket pin78. It will be understood that the socket pins 78 are inserted in eachof the bores 42 of the lower plate 16, and the pins 80 are nested in thesocket-pins 78, prior to the assembly of the unit 10. Consequently, withthe pins so carried in the bores 42 of the lower plate 16, registry isautomatically effected when the upper plate 16 is superimposed over thelower plate so that the nested'pins 80 extend into the bores 42 in theupper plate 16, being seated in the enlarged seats 44A defined in thesurface 18 of the upper plate. In this connection, it will be understoodthat before the plates 16 are mounted in superimposed relation, asdescribed, the diaphragm 14 is inserted therebetween so that when theplates are assembled, as illustrated in Fig. 2, the pins 78 and 80extending between the two plates in the aligned bores 42 of the twoplates, the grooves 20 at the opposite sides of the diaphragm 14 are inautomatic registry. The backing members 44 are then disposed in abutmentwith the outer surfaces of the dialyzer plates 16, as illustrated, andthe clamps 46 are disposed so that the rims 60 thereof engage in thegrooves 58 formed in the outer surfaces of members 44. The entire unitis mounted over the spill plate 70 with the stud 48 extendingtherethrough, as illustrated. In this connection, it will be noted thatthe check nut 62 serves as a shoulder in abutment with the lower surfaceof the spill plate 70 so that the threaded adjustment of thenut 50 onthe stud 48 serves to apply clamping pressure between the nuts 50 and 62through the clamps 46' to the pressure transmitting members 44 andthrough the latter to the dialyzer plates 16. The nut 50 may beconveniently adjusted to supply the desired degree of clamping pressureby a suitable spanner wrench '84 which is adapted to-engage in theopenings 68 provided in the nut 50, as. illustrated-in phantom in Fig.1.

It will be noted that the clamping pressure'wis. applied by the clamps46 to the flexible members 44 along the line of contact therebetween and.morespecificallyat.

.4 the line where each rim 60 is engaged in the complementary groove 58.It will be noted that this line of contact overlies the area of theplates 16 in which the grooves 20 are defined so that the clampingpressure is provided in the needed area, namely the area in which themembrane 14 is iuterposedbetween the grooves 20 so as to define fluidpassages at the opposite sides of the membrane. The clamping pressure isapplied evenly to thedialyzer plates 16 due to the previously describedflexibility provided in the members 44 resulting from the aperturedconstruction thereof in which much of the material is removed therefromby the holes 52. The clamping pressure evenly applied to the plates 16along a circle at each plate over the area thereof in which the groove20 is defined, prevents any tilting or separation of the platesresulting from the application of the clamping pressure so that themembrane remains in fluid tight relation between the plates.

The previously described stepped formations 40A provided, in themarginal edges of the dialyzer members 16 define a continuous peripheralnotch 84A in the dialyzer unit 10. The notch 84A is adapted for theready reception of a screw driver, or similar tool, which can be used toseparate the dialyzer members 16, when the unit is disassembled, if saidmembers should stick together due to the clamping pressure appliedthereto.

The previously described registry of the grooves 20 by the nested pinsand 78 also effects the registry of the inlets and outlets of each ofthe plates 16. More specifically, it will be noted that the two nipples36 which extend into the aligned notches 28 of the plates 16 are inalignment, as are the two nipples 36 which extend into the alignednotches 30 of the plates as best illustrated in Fig. 5. Consequently,the conduits 38 which are secured to each pair of aligned nipples arealso in alignment. For example, as best illustrated in Fig. 1, theconduits 38 at the inlet nipples of the upper and lower plates 16 arealignedfor fluid flow into the dialyzer through the inlet terminals 32of the grooves 20, as indicated by the arrows -90 in Fig. 1. Similarly,the output nipples are aligned, and the associated conduits 39 thereofare in alignment for the flow of the fluids from the output terminals ofthe grooves 20, out of the dialyzer, as indicated by the arrows 92-92.Consequently, it will be noted that the inlet and outlet of each plate16 is readily accessible at the same marginal edge portion of each platealong the outer edge thereof, this resulting from the reversal of fluidthrough each groove 20 due to the reflexed portion thereof. Saidreflexed spiral groove arrangement results in a greatly increased numberof convolutions per area unit of each plate 16.

The alignment of the inlets and outlets of the dialyzer plates 16 isadvantageous in permitting a comparison to be made of the flows in eachof the inlet conduits 38 and of the flows in each of the outlet conduits39. However, it will be understood that insofar as other features of thepresent invention are concerned, the inlet and outlet of the upper plateneed not be in alignment with the inletand outlet of the lower plate.

In the presently preferred form of the invention illustrated by Figs.6-9, the dialyzer apparatus comprises a plurality of dialyzer sections10A disposed in superposed stacked relation, whereby the operativecapacity of the dialyzer can be increased without increasing thediameter of the apparatus. In this connection, it may be observed thatwhile only two dialyzer sections 10A are illustrated, the dialyzerapparatus may include three or more dialyzer sections. The plates aregrooved preferably in the same way as described above to provide thefluid passages and each plate has a fluid inlet and an outlet. In Figs.6 to 9, the parts which are the same as the parts provided in the formof the invention illustrated by Figs. 1 to 5 are designated by the samereference'numerals. It will be understood that the dialyzer sections 10Aare connected :inseries fluid-flow relation;

that is, the outlet 39 of the passage in the upper plate of the uppersection A, is connected to the inlet 39A of the passage in the upperplate of the lower section 10A, and correspondingly, the outlet 41 ofthe lower passage in the upper section 10A is connected to the inlet 41Aof the lower passage in the lower plate of the lower section 10A.

Also, pursuant to the preferred embodiment of the invention illustratedby Figs. 6 to 9, an improved clamping device is provided whereby to makeit easier both to clamp and to unclamp the companion plates and theassembly. For this purpose the clamping nut 50A and the clamping member66A which is in frictional engagement with the upper clamping plate 46are provided with an interposed anti-friction or ball bearing device 94.This device is constituted by the circular grooves 95 and 96 in members50A and 66A, respectively, forming a ball bearing race for the balls, asillustrated (Fig. 4). A split spring ring 98 holds member 66A inposition in its assembly with member 50A, while allowing member 50A tobe turned in screw-threaded engagement with stud 48 without turning thefriction clamping member 66A. It

will be understood that since member 50A does not engage clamping member46 and has an antifriction engagement with clamping member 66A it iseasier to turn said member 50A in performing the clamping and unclampingoperations and considerable clamping pressure may be provided withcomparatively little effort.

The grooves in the companion plates of each section are registered witheach other by the pin and socket devices 78A, 80A, in the same way asthe pin and socket devices 78, 80 described above, and in addition thepins 78A are long enough, as shown in Fig. 8, to engage in registeringopenings 80B in the adjacent plate of an adjacent section.

This application is a continuation-in-part of my United Statesapplication Serial No. 620,065, filed November 2, 1956, now abandoned.

While I have shown and described the preferred embodiments of myinvention, it will be understood that various changes may be madetherein without departing from the underlying [in] idea or principles ofthe invention within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. A dialyzer comprising a plurality of sections disposed in adjacentconfronting relation, each of said sections comprising a pair of platemembers mounted in confronting face-to-face relation, a dialyzermembrance interposed in fluid tight relation between the confrontingfaces of said members, said confronting face of each member having acontinuous spiral groove defined therein, said groove being reflexedsubstantially midway along the extent thereof and the opposite endsthereof terminating substantially at the outer marginal edge of theassociated plate and having a fluid inlet and a fluid outlet adjacentsaid inlet, respectively, said grooves constituting fluid passages, theoutlets of the passages of one of said sections being connected to theinlets of the passages of another section at the similar sides,respectively, of the membranes of said sections, respectively.

2. A dialyzer, comprising a plurality of sections disposed in adjacentconfronting relation, each section comprising a pair of plates and aninterposed membrane, said plates having fluid passages, disposed atopposite sides, respectively, of the companion membrane, and fluidinlets and outlets for said passages, the outlets of the passages of oneof said sections being connected to the inlets of the passages ofanother section at the similar sides, respectively, of the membranes ofsaid sections, respectively, annular backing members disposed inclamping relation between the adjacent plates of adjacent sections,annular backing members in clamping relation with the other plates ofsaid sections, respectively, said last mentioned backing members eachhaving a circular 6 groove and means for clamping said last mentionedbacking members against said other plates, respectively, said clampingmeans each having a circular lateral projection complementary to and inabutting relation with the circular groove on the associated backingmember, and thereby releasably clamping the companion plates together atopposite sides of the companion membrane and also releasably clampingsaid sections together in said unitary relation whereby to apply evenpressure to said plates and provide a fluid tight joint between theplates of each section and the membrane therebetween.

3. A dialyzer, comprising a plurality of sections disposed in adjacentconfronting relation, each section comprising a pair of plates and aninterposed membrane,

each confronting face of said plates having a continuous groove definedtherein forming fluid passages disposed at opposite sides, respectively,of the companion membrane, each of said grooves being a spiral groovewhich is reflexed substantially midway along the extent thereof, andfluid inlets and outlets for said passages, the outlets of the passagesof one of said sections being connected to the inlets of the passages ofanother section at the similar sides, respectively, of the membranes ofsaid sections, respectively, annular apertured backing members disposedin clamping relation between the adjacent plates of adjacent sections,annular apertured backing members in clamping relation with the otherplates of said sections, respectively, and means for exerting pressurealong a circular line of contact to said last mentioned backing membersto clamp the latter against said other plates, respectively, and therebyreleasably clamping the companion plates together at opposite sides ofthe companion membrane and also releasably clamping said sectionstogether in said unitary relation, said last mentioned means comprisinga stud extending axially through said assembly and means adjustablymovable in relation to said stud for exerting pressure on said backingmembers in the direction of the axis of said stud, said adjustablymovable means being mounted on a roller bearing for rotation relativesaid stud.

4. A dialyzer, comprising a plurality of sections disposed in adjacentconfronting relation, each section comprising a pair of plates and aninterposed membrane, each of said plates having a continuous fluid flowgroove free of obstructions disposed at opposite sides respectively, ofthe companion membrane, fluid inlets and outlets for said grooves, theoutlets of the grooves of one of said sections being connected to theinlets of the grooves of another section at the similar sides,respectively, of the membranes of said sections, respectively, and meansfor clamping the membrane in each section in fluid tight relationbetween the associated plates and for clamping said sections together insaid confronting relation, said clamping means including backing membersdisposed in clamping relation between adjacent plates of adjacentsections, a pair of backing members each having one surface thereofdisposed in abutment with the outer plate of the outer sections,respectively, and a clamping member disposed at the other surface ofeach of said pair of backing members and operable thereon to exert theclamping pressure thereto along a circular line of contact.

5. A dialyzer, comprising a plurality of sections disposed in adjacentconfronting relation, each section comprising a pair of plates and aninterposed membrane, each of said plates having a continuous fluid flowgroove free of obstructions disposed at opposite sides respectively,ofthe companion membrane, fluid inlets and outlets for said grooves, theoutlets of the grooves of one of said sections being connected to theinlets of the grooves of another section at the similar sides,respectively, of the membranes of said sections, respectively, and meansfor clamping the membrane in each section, in fluid tight relationbetween the associated plates and for clamping said sections together insaid confronting relation, said clamping means including backing members7 disposed in clamping:relationbetween adjacent plates of adjacentsections, a pair of backing members each having one surface thereofdisposed in abutment with the outer plate of the outer sections,respectively, and a clamping member disposed at'the other surface ofeach of said pair ofbacking members and provided with a lateral circularprojection which abuts the latter in registry with the fluid flowgrooves, and means to urge said clamping members together against saidpair of backing 1 members along a circular line of contact fortheapplication of even pressure to said plates within the area of saidgrooves to provide a fluid tight joint between the plates of eachsection and the membrane therebetween at said flow grooves.

6. A dialyzer, comprising a plurality of sections disposed in adjacentconfronting relation, each section comprisingya pair of plates and aninterposed membrane, each confronting face of said plate having acontinuous groove defined therein forming fluid passages disposed atopposite sides, respectively, of the companion membrane, each of saidgrooves being a spiral groove which is reflexed substantially midwayalong the extent thereof, and fluid inlet and outlets for said passages,the outlets of the passages of one of said sections being connected tothe inlets of the passages of another section at the similar sides,respectively, of the membranes of said sections, respectively, annularapertured backing members disposed in clamping relation between theadjacent plates of adjacent sections, annular apertured backing membersin clamping relation with the other plates of said sections,respectively, and means for exerting pressure along a circular line ofcontact to said last mentioned backing members to clamp the latteragainst said other plates, respectively, and thereby releasably clampingthe companion plates together at opposite sides of the companionmembrane and also releasably clamping said sections together in saidunitary relation, said pIates beingtransparent whereby said grooves arevisible through'the apertures in said backing members.

7. A dialyzer comprising a pair of plate members mounted in confrontingface-to-face relation, a dialyzer membrane interposed in fluid tightrelation between the confronting faces of said members, each of saidmembers having a continuous groove free of'obstructions defined thereinfor providing for the flow of fluid along the adjacent surface of saidmembrane, the groove in the plate at one side of said membrane being inregistry with the groove of the other plate at the-opposite side of themembrane, each of said grooves-having an inlet and an outlet, and boththe ,inlet and the outlet of each plate being located at the outermarginal edge'thereof and in adjacent relation to each other.

8. A dialyzer comprising a pair of plate members mounted in confrontingface-to face relation, a dialyzer membrane interposed in flu-id tightrelation between the confronting faces of said members, said confrontingface of each member having a continuous groove defined therein, thegroove in the plate at' one side of said mem brane being in registrywith the groove of the other plate at the opposite side of the membrane,said groove being a spiral groove which is reflexed' substantiallymidway along the extent thereof and having the opposite ends thereofterminating substantially at the outer marginal edge of the associatedplate and having a fluidinlet and a fluid outlet, respectively.

9. A dialyzcr comprising a pair of plate members mounted in confrontingface-to-face relation, a dialyzcr flow'means havingan inlet and anoutlet, and both the inlet and the outlet of each plate being located atthe outer marginal edge thereof, and means to apply an evenclampingpressure to-said plates-to clamp said membrane in fluid 'tightrelation therebetween, said clamping pressure means includinga pressuretransmitting member operable on each plate to apply the clampingpressure evenly thereto, and a clamping plate having a circularprojection operable on each pressure transmitting member to exert theclamping pressure thereto along a air-- cular line of contact.

10. A dialyzer comprising a dialyzer membrane mounted between a pair ofplate, the confronting-surfaces of said plateseach' having a fluid flowgroove defined therein for fluid flow along the adjacent surface of saidmembrane, a pair of backing members each having one surface thereof inabutment with the other surface of one of said plates, a'clamping memberdisposed at the other surface of each backing member and provided with alateral circular projection which abuts said other surface of theassociated backing member in registry with the fluid flow groove of theassociated plate, and means to urge said clamping members togetheragainst said backingmembers along a circular line of contact for theapplication of an even clamping pressure to said plates within the areaof said grooves to provide a fluid tight joint between the dialyzerplates and the membrane at said flow grooves.

11. A dialyzer comprising a dialyzer membrane mounted between a pair ofplates, the confronting surfaces of said plates each having a fluid flowgroove defined therein for fluid flow along the adjacent surface of saidmembrane, a pair of relatively thin apertured backing members eachhaving one surface thereof in abutment with the other surface of one ofsaid plates, the other surface of each of said backing members having acircular groove, a clamping member disposed at said other surface ofeach backing member and provided with a lateral circular projectioncomplementary to and abutting said groove at 'said other surface of theassociated backing member "along a circular line of contact in registrywith the fluid flow groove of the associated plate, and means to urgesaid clamping members together against said backing members along saidcircular line of contact for the application of an even clampingpressure to said plates within the area of said flow grooves to providea fluid tight joint between the dialyzer plates and the membrane at saidflow grooves.

12. A dialyzer comprising a pair of plate members mounted in confrontingface-to-face relation, (1 dialyzer membrane interposed in fluid tightrelation between the confronting faces of said m'embers, each of saidmembers having means providing for the flow of fluid along the adjacentsurface of said membrane, each of said fluid flow means having an inletand an outlet, and both the inlet and the outlet of each plate beinglocated at the outer marginal edge thereof, and means to apply an evenclamping pressure to said plates to clamp said membrane in fluid tightrelation therebetween, said clamping pressure means including a pressuretransmitting member operable on each plate to apply the clampingpressure evenly thereto,-and a clamping plate having a circular riboperable on each pressure transmitting member to exert the clampingpressure thereto along a circular line of contact, said pressuretransmitting members being apertured and said plate members beingtransparent whereby said flow means are visible through the apertures ofsaid pressure transmitting members, respectively.-

13. A dialyzer comprising a dialyzer membrane mounted between a pair ofplates, the confronting surfaces of said plates each having a fluid flowgroove de fined therein for fluid flow along the adjacent surface ofsaid membrane, 'a pair of backing members each having one surfacethereof in abutment with the other surface of one of said plates, aclamping member disposed at the other surface of each backing'member andprovided with a lateral circular projection which abuts said other surface of the associated backing member in registry with the fluidflow-groove of the associated plate, and means to urge said clampingmembers together against said backing members along a circular line ofcontact for the application of an even clamping pressure to said plateswithin the area of said grooves to provide a fluid tight joint betweenthe dialyzer plates and the membrane at said flow grooves, said urgingmeans comprising a stud extending through said clamping members, saidbacking members, said plates and said membrane, a shoulder defining partprovided outwardly of one of said clamping members and an adjustable nutprovided outwardly of the other of said clamping members.

14. A dialyzer comprising a pair of plate members mounted in confrontingface-to-face relation, a dialyzer membrane interprosed in fluid tightrelation between the confronting faces of said members, said confrontingface of each member having a continuous groove defined therein, saidgroove being a spiral groove which is reflexed substantially midwayalong the extent thereo and having the opposite ends thereof terminatingsubstantially at the outer marginal edge of the associated plate andhaving a fluid inlet and a fluid outlet, respectively, a pair ofrelatively thin apertured backing members each having one surfacethereof in abutment with the other surface of one of said plates, theother surface of each of said backing members having a circular groove,a clamping member disposed at said other surface, of each backing memberand provided with a lateral circular projection complementary to andabutting said groove at said other surface of the associated backingmember along a circular line of contact in registry with the fluid flowgroove of the associated plate, and means to urge said clamping memberstogether against said backing members along said circular line ofcontact for the application of an even clamping pressure to said plateswithin the area of said flow grooves to provide a fluid tight jointbetween the dialyzer plates and the membrane at said flow grooves.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS 1,928,182 Mahoney Sept. 26, 1933 2,076,049 SeitzApr. 6, 1937 2,252,213 Skolnik Aug. 12, 1941 2,389,814 Pond et a1 Nov.27, 1945 2,708,658 Rosenberg May 17, 1955

